降雨条件下边坡体积含水率变化规律研究

Study on the Variation Law of Volumetric Water Content of Slope Under Rainfall Conditions

持续降雨是边坡发生失稳破坏的主要诱因之一,基于饱和—非饱和渗流理论,对梅州市大埔县某边坡的渗流场进行模拟,研究在不同降雨工况下该边坡土体体积含水率的时空变化规律。研究结果表明:相同条件下,降雨强度越大(降雨历时越长),边坡表层土体体积含水率变化越大;降雨强度60 mm/d历时1 d的暴雨对边坡表层土体体积含水率的增幅作用存在着一定的滞后性,其余工况未表现出滞后现象;降雨强度为120mm/d和300 mm/d的两种工况各研究点任意时段体积含水率较为接近;当降雨强度达到60 mm/d以上时,边坡内部体积含水率空间变化主要受降雨历时影响,降雨历时越长,降雨入渗深度和体积含水率变化越大。

Continuous rainfall is one of the main causes of instability and failure of slope,Based on the saturated-unsaturated seepage theory,this paper simulates the seepage field of a slope in Dapu County,Meizhou City,and studies the temporal and spatial variation of the volumetric water content of the slope under different rainfall conditions. The results show that: under the same conditions,the greater the rainfall intensity(the longer the rainfall duration),the greater change the volumetric water content of the slope surface soil. The rainstorm with a rainfall intensity of 60 mm/d and a duration of 1d has a certain hysteresis on the increase of the volume moisture content of the surface soil on the slope, while the rest of the working conditions do not show hysteresis. When the rainfall intensity was 120 mm/d and 300 mm/d respectively, the volumetric moisture content of each research point at any time period was relatively close to each other;When the rainfall intensity reaches 60 mm/d or more,the spatial change of volume water content inside slope is mainly affected by the duration of rainfall. The longer the duration of rainfall,the greater the change of rainfall infiltration depth and volume water content.